Which one of the following is FALSE?

2014

Which one of the following is FALSE?

  1. A.

    A basic block is a sequence of instructions where control enters the sequence at the beginning and exits at the end

  2. B.

    Available expression analysis can be used for common subexpression elimination

  3. C.

    Live variable analysis can be used for dead code elimination

  4. D.

    x = 4 * 5 ⇒ x = 20 is an example of common subexpression elimination

Attempted by 29 students.

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Correct answer: D

The question asks to identify the false statement about compiler optimizations. Option 3 incorrectly claims constant folding is an example of common subexpression elimination. Constant folding evaluates expressions at compile time, while CSE removes redundant calculations. Options 0, 1, and 2 correctly describe basic blocks, available expressions, and live variables respectively.

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